The pyrrolizidine alkaloids and their N-oxides will be isolated from the following Israeli plants: Heliotropium maris mortui, H. rotundifolium, H. arbainense, Senecio jobensis, S. vernalis, Cynoglossum creticum, Trichodesma africanium, Crotalaria aegyptica. The extracts and pure alkaloids will be submitted to the National Cancer Institute for screening and pharmacological studies of these will be made using mice. The plant extracts will also be investigated for the presence of suspected furanosesquiterpenes and sesquiterpenoid lactones.